Immune System & the Brain: How Do They Interact?

Long ago, it was thought that the immune system and the brain were two separate entities that didn’t have any interaction. New research suggests that is not quite the case. 

We’ll unpack the research, talk about how the brain and immune system work together, and discuss the importance of this relationship. We’ll also talk about how an essential fatty acid could be the key to helping keep the cells in your brain and your immune system healthy. 

First, let’s talk about how the immune system works. 

The Immune System at a Glance 

You already know the immune system is a complex series of organs, white blood cells, proteins, and chemical compounds that work together to protect your body against infection and disease. 

When bacteria, viruses, parasites, or really any foreign particle enters your body, and your body decides that foreign particle doesn’t quite belong, white blood cells are deployed to eliminate the threat. Your lymph nodes will then help to expel them from the body. 

Another property of the immune system is the creation of antibodies. Antibodies recognize the germ you’ve been infected with previously and help prevent you from becoming sick with it again, like the body’s own built-in vaccination. 

Of course, this is an incredibly simplified look at how immunity works. The immune system can also malfunction, as it does in the case of autoimmune diseases. When this happens, the immune system attacks the body’s own cells, produces inflammatory cells called interleukins and leukocytes, and causes chronic inflammation. 

The immune system was thought to be self-regulatory for many years, but we now know that isn’t the case. Let’s talk about how brain signaling works (briefly) and then discuss the relationship between brain signaling and the immune system.

Brain Signaling

The cells within the brain (called neurons) talk to one another through a series of synapses between neurotransmitters. These synaptic transfers control virtually every bodily process and help regulate our overall balance or homeostasis. 

The immune system has its own communication system, but scientists have long believed these two communications systems were separate. 

The Brain and Your Immune System

The theory of immune privilege states that the brain is completely cut off from the immune system. This was popularly believed because if the brain were involved, there could be a chance that microbes or other germs could pass from the immune system to the brain. 

The brain has a built-in protection feature known as the blood-brain barrier. It was thought that the cells and signals of the immune system couldn’t penetrate the blood-brain barrier. Recent studies have discovered lymphatic vessels near the brain's surface, which suggests that the blood-brain barrier isn’t completely immunologically privileged. 

We know now that the brain and immune systems are intertwined; the immune system messages the brain, and the brain influences the immune system. 

How Do the Brain and Immune System Interact?

As it turns out, the brain and the immune system have been talking for a long time; we just didn’t realize it. The discovery of lymphatic vessels on the brain's surface has led researchers to discover that the brain and immune system are in constant contact. 

Immune cells and lymphocytes (a certain type of white blood cell) have receptors on their membranes that can send and receive messages with neurotransmitters in the brain. 

When these cells are activated as part of immune activation, the body produces an immune response. The signals originate in specific immune cells in this specific communication between the brain and the immune system. 

There are two specific types:

• Monocytes: These are a large type of phagocytic white blood cell. This type of cell finds a bacterial cell and removes it from your system.
• Macrophages: This is another type of bacteria-seeking white blood cell that engulfs threats to neutralize them. 

These cells use a special type of protein, a cytokine, to send messages to the brain that a pathogen is present and changes are needed. When cytokines are present, so is inflammation, which could mean bad news for your brain. Luckily, the brain has its own built-in immune system. 

The Brain’s Immunity

Just like the immune system is home to immune cells, the brain creates its own specialized immune cells called microglia. In addition, the meninges (the brain's outer covering that includes the blood-brain barrier) is packed with immune cells like T cells and macrophages.

The brain makes immune cells inside your bone marrow in the skull, and we know that these cells in the brain are often higher in cerebrospinal fluid tests of people who have suffered a brain injury or neurological disease. 

Why the Connection Matters

The discovery of the lymphatic vessels near the brain can possibly help us better understand neurological diseases like multiple sclerosis, Alzheimer’s disease, and autism. These diseases are thought to occur when lymphatic system waste collects in brain tissue. 

In addition, the messages sent from the immune system to the brain may play a role in these diseases by causing inflammatory responses in the brain. This is because pro-inflammatorycytokines can pass into certain brain parts that are not protected by the blood-brain barrier, called circumventricular areas.

Protecting Your Immunity and Your Brain

Keeping your brain sharp and staying well are certainly worthy goals. In addition to eating a balanced diet, getting plenty of exercise, sleeping well, and managing stress, we often look for other ways to support these systems. Science says there’s a simple way to do it. 

Foundational Health

The foundation of our health begins in our cells. Ensuring our cells are properly working can translate into healthier tissues, organs that function well, and entire bodily systems that run smoothly. 

The problem is our cells wear out. As we age, they become weak, which means tissues, organs, and systems begin to decline and eventually fail. Supporting our cells, then, can mean supporting a healthier lifestyle from the ground up. 

It might seem like a tall order, but science says a certain fatty acid can help do the job. 

Pentadecanoic Acid

Pentadecanoic acid, also known as C15:0, is an odd-chain, saturated fatty acid that is the first essential fatty acid to have been discovered since the omegas over 90 years ago. Essential means our bodies need it to thrive but cannot readily make it on their own. 

Although we have heard that all saturated fats are bad for us, science now supports that that is not the case. C15:0 is an odd-chain, saturated fatty acid that has recently been discovered to be an essential fatty acid. Meaning our bodies cannot make C15:0 and therefore, we must get it from our diet to maintain our health and wellness.

Science supports that higher levels of C15:0 is associated with better metabolic, immune, liver, and heart health.*

What Does C15:0 Do?

C15:0 helps support your cells in a few key ways:*

• Cell membrane structure. A sturdy fatty acid, C15:0 integrates itself into cell membranes, helping fortify your cells and keep them strong. 

• Mitochondrial function. Aging cells have declining mitochondrial function, translating into less energy within the cell and less energy in your body. C15:0 helps recharge your cells’ mitochondria by 45 percent. 

• Improved cellular signaling. The messages transmitted between cells help every system in our body function the way it should. When our cells lose this ability to communicate effectively, systems like immunity, sleep, and even mood can deteriorate quickly. C15:0 helps restore balance by binding to specialized receptors called PPARs, which regulate these cellular communications. 

In addition, C15:0 has repeatedly been associated with healthy cholesterol and triglyceride levels and improved heart health.*

How To Get C15:0

C15:0 is primarily found in trace levels in whole-fat dairy products. However, simply increasing your intake of whole-fat dairy products comes with extra calories, sugars, and high levels of the "bad", pro-inflammatory even-chain saturated fats.

A solution? Fatty15.

Fatty15: Support for Your Entire Body

Fatty15 is the first and only supplement to contain FA15™, the pure, sustainably produced vegan-friendly, award winning version of C15:0. 

Transparently, protecting your brain health and immune function in full is no easy feat and won’t be accomplished with a single supplement, but one way you can help your body help you is by supporting it at its foundational levels: your cells.

Just one capsule per day is all you need to restore your circulating levels of C15:0 to give your cells the support they need to do their jobs for a very long time.*

Sources:

[Relationships between the brain and the immune system]|PubMed.NCBI.NLM.NIH.gov

Immune activation in the central nervous system throughout the course of HIV infection - PMC

Brain's Link To Immune System Might Help Explain Alzheimer's|Npr.org

Guardians of the brain: how a special immune system protects our grey matter|Nature.com